Electric motors are employed in some very precise applications. One example is as a drive motor in a tape drive. There are any number of tape drives that are commonly used. A typical tape drive includes two reel assemblies. A first reel assembly consists of a removable cartridge that is loaded into the tape drive. The first reel holds a length of tape. A first drive motor is coupled to the first reel. The second reel assembly is often permanently mounted in the tape drive and is connected to a second drive motor. The tape from the first reel is threaded onto the second reel and the two drive motors work together to shuttle the tape back and forth between the two reels. Many operating parameters of the drive motors should be tightly monitored or controlled. Among these parameters, depending on the application, might be the speed and start/stop regulation.
A drive motor may contain any number of electrical components including the motor itself. Some of the components may be in the form of an Integrated Circuit (IC) such as an Application Specific Integrated Circuit (ASIC) and some of the components may be in the form of discrete electrical components such as resistors, capacitors, and Operational Amplifiers (op amps). The exact combination of components and the values for those components may depend on various factors such as operational environment and designer preference. Each of the components will have various design and manufacturing tolerances. To assure proper operation of the drive motor, such tolerances should be accounted for. In practice, this might be accomplished in one or more steps during manufacturing of the drive motor. For example, one or more operational parameters can be calibrated to fall within a suitable range. Various adjustments are made to fine tune operation of the drive motor to achieve accurate calibration. The drive motor may or may not be calibrated several times over its useful life.